eth/downloader: prioritize block fetch based on chain position, cap memo...

p2p: more last-minute fixes

This should improve ethereum block propagation times since
we're not not broadcasting blocks to 100% of peers.

With the introduction of static/trusted nodes, the peer count
can go above MaxPeers. Update the capacity check to handle this.
While here, decouple the trusted nodes check from the handshake
by passing a function instead.

p2p: throttled handshakes

Otto.ToValue concurrency error fixed

jsre, cmd/geth: updated web3.js and altered settimeout

Test updates

solidity compiler and contract metadocs integration

xeth, core, event/filter, rpc: new block and transaction filters

Update ethash deps (more build fixes, tests)

* common/compiler: solidity compiler + tests
* rpc: eth_compilers, eth_compileSolidity + tests
* fix natspec test using keystore API, notice exp dynamically changes addr, cleanup
* resolver implements registrars and needs to create reg contract (temp)
* xeth: solidity compiler. expose getter Solc() and paths setter SetSolc(solcPath)
* ethereumApi: implement compiler related RPC calls using XEth - json struct tests
* admin: make use of XEth.SetSolc to allow runtime setting of compiler paths
* cli: command line flags solc to set custom solc bin path
* js admin api with new features debug and contractInfo modules
* wiki is the doc https://github.com/ethereum/go-ethereum/wiki/Contracts-and-Transactions